The diagnosis of ECRS has unique prognostic implications. Traditional features of the ECRS phenotype are not necessarily reliable markers for the presence of tissue eosinophilia. Serum eosinophilia may be a good surrogate marker of tissue eosinophilia but of limited use. The routine use of structured histopathology reporting in CRS is suggested, to allow for the diagnosis of ECRS and to identify other prognostic markers.

The philosophical approach to ESS in CRS is evolving. Topical therapies, when used appropriately, are highly effective for the most challenging eosinophilic patients. Although corticosteroid is a nonspecific therapy, it is effective when appropriately delivered.

The classification of neoplasms of adenohypophysial cells is misleading because of the simplistic distinction between adenoma and carcinoma, based solely on metastatic spread and the poor reproducibility and predictive value of the definition of atypical adenomas based on the detection of mitoses or expression of Ki-67 or p53. In addition, the current classification of neoplasms of the anterior pituitary does not accurately reflect the clinical spectrum of behavior. Invasion and regrowth of proliferative lesions and persistence of hormone hypersecretion cause significant morbidity and mortality. We propose a new terminology, pituitary neuroendocrine tumor (PitNET), which is consistent with that used for other neuroendocrine neoplasms and which recognizes the highly variable impact of these tumors on patients.

Germline succinate dehydrogenase B (SDHB) mutation causes pheochromocytoma/paraganglioma syndrome type 4 (PGL4). PGL4 is characterized by pheochromocytoma and paraganglioma, type 2 (SDHB negative) gastrointestinal stromal tumors and renal tumors, which are usually classified as carcinoma. We report 4 kindreds with 5 PGL4-associated renal tumors. Four of the tumors occurred before the age of 30 years, 4 were in the left kidney, 3 were in female patients, and 4 demonstrated consistent but previously unrecognized morphology. The tumors were composed of cuboidal cells with bubbly eosinophilic cytoplasm and indistinct cell borders. Many of the cells displayed distinctive cytoplasmic inclusions, which were vacuolated or contained eosinophilic fluid-like material. The cells were arranged in solid nests or in tubules surrounding central spaces. The tumors were well circumscribed or lobulated and frequently showed cystic change. Benign tubules or glomeruli were often entrapped at the edges of the tumors. The fifth tumor lacked these features but displayed sarcomatoid dedifferentiation. Immunohistochemistry for SDHB was completely negative in all 4 available tumors. Death from metastatic disease occurred in the patient with dedifferentiated tumor 1 year after diagnosis, whereas the other 4 tumors were cured by local excision alone (mean follow-up, 11 y; range, 2 to 30 y). We conclude that morphology supported by negative immunohistochemistry for SDHB can be used to identify kindreds with germline SDHB mutations (PGL4 syndrome) presenting with this unique type of renal tumor. These renal tumors appear to have a good prognosis after complete excision unless there is sarcomatoid dedifferentiation.